1. Field of the Invention
The present invention pertains to optoelectronic devices and packages. The invention more particularly concerns a high density optoelectronic device such as an array which includes multiple, modular transmitters and/or receivers.
2. Discussion of the Background
Optoelectronic devices such as optical transceivers are known in the art and include active optical devices or diode packages. Common diode packages include LED packages such as a TO-46 package or a 5.6 mm TO style laser diode package such as an RLD-85PC diode package by Rohm, Incorporated. These diode packages or TO cans typically include a metallic housing having a laser diode or LED for transmitting data and a photo diode for performing power-monitoring, metal contact leads exiting from the diodes for connection to a power source and a cover glass opposed to the diode, through which the energy is transmitted. Discussion of the power-monitoring and feedback control of the laser diode by the photo diode is presented in U.S. Pat. Nos. 5,812,582 and 5,815,623. U.S. Pat. Nos. 5,812,582 and 5,815,623 are hereby incorporated herein by reference. The TO can is hermetically sealed. Often, optics housings are metallic so as to provide ruggedness, ease of machining complicated shapes, and to enhance shielding of electromagnetic fields.
Smaller optoelectronic packages allow the devices into which the optoelectronic packages are placed to become smaller. Smaller optoelectronic packages allow for a higher density of data transmission in a given space. Currently, there is a great demand for smaller optoelectronic packages.
FIG. 8 is a partial cross-sectional pictorial view of an optoelectronic package 200. The optoelectronic package 200 includes a base element 212, posts 206, 208, 210, extending through the base element 212 and secured thereto with solidified molten glass 214, a monitor diode 204 mounted on the base element 212, an optical emitting element 202 mounted on the monitor diode 204, a can 218 and lens 216 enclosing the monitor diode 204 and the optical emitting element 202. In an effort to reduce space, the optical emitting element 202 is mounted on top of the monitor diode 204. Electrically conductive posts 206, 208, 210 extend through through-holes in the electrically conductive base element 212. The posts 206, 208, 210 are electrically insulated from the base element 212 by solidified molten glass 214 which also attaches the posts 206, 208, 210 to the base element 212. The posts 206, 208, 210 are large as compared to the other components and require a large area for their mounting and placement.
At minimum, the diameter across the base element 212 is approximately 3.8 millimeters, as incorporated on the SLT2160-LN series of transmitter optical sub-assemblies manufactured by Sumitomo Electric Industries, Ltd. Thus, if two of these devices are placed side-by-side, on the same plane, the distance between the optical axes is, hypothetically, at best, 3.8 millimeters. However, typically, the optical axes are separated by 6.25 millimeters, due to packaging constraints as in typical LC duplex transceivers such as Methode Electronics, Inc.""s, part number MLC-25-4-X-TL which is described in the data sheet entitled, xe2x80x9cMLC-25-4-X-TL Optical Gigabit Ethernetxe2x80x94+3.3V Small Form Factor (SFF) Transceiverxe2x80x941.25 GBaud.xe2x80x9d Furthermore, the MLC-25-4-X-TL transceiver includes a transmitter and a receiver hardwired to the device.
Therefore, it is an object of the present invention to provide a high density optoelectronic device or array which includes optoelectronic subassemblies such as transmitters and receivers.
It is still another object of the invention to provide an optoelectronic device which includes modular components so as to enable the custom assembly of an array of transmitters or an array of receivers or an array of a combination of transmitters and receivers.
It is yet another object of the invention to provide an arrayed device having modular components so that individual components, such as transmitters and/or receivers, can be easily removed or inserted for replacement, repair, or changed operating parameters.
It is a further object of the invention to provide an optoelectronic device which is easy to install, and provides for more efficient utilization of limited space.
It is another object of the invention to provide an optoelectronic device which is inherently eye safe.
In one form of the invention, the one channel sub-assembly includes a small format optical subassembly attached to an optical coupling element and a substrate. The optical coupling element includes a focusing element, and a ferrule receiving bore. The small format optical subassembly is attached to the optical coupling element. The optical coupling element may also include a metal portion, where the metal portion is laser welded to the small format optical subassembly. Furthermore, the one channel sub-assembly may be an optical transmit channel or an optical receive channel.
In another form of the invention, the device includes two one channel sub-assemblies, where each one channel sub-assembly is constructed as discussed in the above embodiment. Furthermore, the ferrule receiving bores of each of the one channel sub-assemblies are parallel to each other. Additionally, each of the ferrule receiving bores are separated by a distance.
In yet another form of the invention, the device includes a housing, first and second one channel sub-assemblies mounted and removeably inserted within the housing, and a cover removeably attached to the housing. The cover and the housing retain the first and second one channel sub-assemblies therein. The device provides for modification and interchangeability of the modularly array one channel sub-assemblies for repair or replacement within the housing.
Thus, the device of the invention is superior to existing optoelectronic devices that include optoelectronic subassemblies. The modular high density multiple transmitter/receiver array of the invention eliminates the use of large, bulky components, and replaces them with a smaller component through use of a unique combination of materials and arrangement of the materials. Thus, the device of the invention is smaller than prior art devices.